tailieunhanh - Báo cáo hóa học: " Physical layer metrics for vertical handover toward OFDM-based networks"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Physical layer metrics for vertical handover toward OFDM-based networks | Oularbi et al. EURASIP Journal on Wireless Communications and Networking 2011 2011 93 EURASIP Journal on . http content 2011 1 93 Wireless Communications and Networking a SpringerOpen Journal RESEARCH Open Access Physical layer metrics for vertical handover toward OFDM-based networks Mohamed Rabie Oularbi Francois-Xavier Socheleau Sebastien Houcke and Abdeldjalil Aĩssa-El-Bey Abstract The emerging trend to provide users with ubiquitous seamless wireless access leads to the development of multimode terminals able to smartly switch between heterogeneous wireless networks. This switching process known as vertical handover requires the terminal to first measure various network metrics relevant to decide whether to trigger a vertical handover VHO or not. This paper focuses on current and next-generation networks that rely on an OFDM physical layer with either a CSMA CA or an OFDMA multiple-access technique. Synthesis of several signal feature estimators is presented in a unified way in order to propose a set of complementary metrics SNR channel occupancy rate collision rate relevant as inputs of vertical handover decision algorithms. All the proposed estimators are non-data aided and only rely on a physical layer processing so that they do not require multimode terminals to be first connected to the handover candidate networks. Results based on a detailed performance study are presented to demonstrate the efficiency of the proposed algorithms. In addition some experimental results have been performed on a RF platform to validate one of the proposed approaches on real signals. 1 Introduction Nowadays we are facing a wide deployment of wireless networks such as 3G LTE WiMAX Wifi etc. These networks use different radio access technologies and communication protocols and belong to different administrative domains their coexistence makes the radio environment heterogeneous. In such environment one possible approach to overcome the spectrum scarcity .